A current comparator technique is applied to four-terminal resistance measurements for obtaining a highly accurate AC resistance bridge at power frequencies of 50 Hz to 60 Hz. The waste material is ignited during its vortical movement. Such may allow transponders to be quickly and efficiently singulated, for example in a single pass, and information read from andor written to singulated transponders. When replaying the script of the operating manual, the script may be stopped at convenient points to add additional operations andor modifications.